How Do I Allocate Home Office Expenses Between Two Businesses?

[Viking99]

In the interview for business 1, I specify that I am using the same home office for another business. 
In the subsequent interview for business 2, I again specify that I am using the same home office for another business. 
However, I am not able to allocate the total expenses between the two businesses, e.g. 60/40. Turbotax just creates two home office deductions with 100% for each.

[Mike9241]

Turbotax uses the business area to total area % to allocate expenses so to do the 60/40 split you will need to split the business area 60/40. there does not appear to be another way to split the expenses 60/40

[Viking99]

So there must be a bug in the program? Turbotax explicitly asks if the Home Office is used by more than one business. However, there is no way thereafter to allocate the expenses between two businesses.